Technical Abstract:
Although the production and sales of ornamental crops represent significant contributions to the global economy, breeding and selection of ornamental plants using molecular markers lags far behind that used for agronomic crops. However, with the recent advances in molecular technologies including relatively inexpensive sequencing of genomes, construction of various nucleic acid libraries, mapping of markers, and a myriad of profiling techniques, discovery and utilization of molecular markers for desirable traits is now possible. Flowering dogwood (Cornus forida L.), native to Eastern North America, is an ornamental tree important to the U.S. nursery industry. In 2009, a genetic linkage map of was constructed using 94 F2 individuals derived from a cross between ‘Appalachian Spring’ and ‘Cherokee Brave’. This map consisted of 255 SSR loci that spanned a total of 1,175 centimorgans (cM) with an average internal distance of 4.6 cM. This was the first linkage map of flowering dogwood and will be a fundamental tool for new gene identification and marker-assisted selection in our breeding program. We have used the segregating F2 population to propose that the inheritance of red foliage color in is a complementary recessive. Additionally, four SSR markers are significantly associated with this novel trait. By applying more SSR markers and developing other molecular markers, such as EST-SSRs, and increasing the mapping population size, a more comprehensive genetic map can be obtained. This work is underway and we are confident that this will allow marker assisted selection of important traits such as bract color and disease resistance.